How should I make my PHP API work for an iPhone app

The title may not be the best way to describe my question.

I am working on another social network type site similar to a facebook site in PHP. I开发者_StackOverflow社区 would like to eventually pay someone to build me an iPhone/iOS app that will be similar to the facebook iPhone app but work with my PHP site instead.

So a major concern for me will be to have the iOS app to be as fast as possible for the users.

From others experience, what would be the best way for my PHP sites API to get the data for the iOS app? I would think that a simple REST type API that returns results with JSON and XML formats would be the way most sites work with an iPhone/iOS app?

Is my theory correct or is there a different way to do it? Please help

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Yes, that's the best solution. The only alternative I know of would be to connect with via TCP/IP, and skip the higher level HTTP protocol. That means using sockets.